We propose to employ molecular techniques to obtain new information on generating immune responses to viral antigens and on inhibiting the synthesis of viruses. This information should prove useful in designing new strategies to combat virus infections. Individual projects involve: the use of anti- idiotype reagents bearing an internal image of the viral antigen to immunize against influenza and HTLV III viruses: the effects of virus-specific anti-sense RNA expression on the replication of influenza virus and spleen focus-forming virus in tissue culture cells; and the generation of transgenic mice expressing anti- sense RNA of influenza virus and spleen focus forming virus.